Enable publishing process context by default (#11288)

Enable publishing process context by default

**What does this PR do?**

This PR changes the default of `PROFILING_PROCESS_CONTEXT_ENABLED` to
`true`, thus enabling publishing of the
[OpenTelemetry process context](open-telemetry/opentelemetry-specification#4719)
by default.

**Motivation:**

When we added this feature, the specification linked above was still a
work-in-progress and that's why we chose to not enable it by default.
As of version 1.62.0 of dd-trace-java we already ship
with the latest version of the spec (that got accepted by
opentelemetry).

Publishing this information will enable the Datadog Full Host Profiler
(which itself is based on the OTel eBPF Profiler) to provide a better
experience when profiling apps using dd-trace-java. (And there's plans
for more features built atop it -- e.g. in the Datadog agent).

This feature is already turned on by default in libdatadog (thus
dd-trace-rb, dd-trace-py, dd-trace-dotnet) + dd-trace-rs + dd-trace-go
and we're working to make sure every lib has it enabled.

**Additional Notes:**

Note that the process context is only supported on Linux, so you won't
see anything on macOS/Linux (outside of docker). The code already
turns those into a no-op, so there's no problem there, just calling it
out for folks interested in testing.

**How to test the change?**

Other than the unit tests, the `otel_process_ctx_dump.sh` script from
[this repo](https://github.com/open-telemetry/sig-profiling/tree/main/process-context/c-and-cpp)
can be used to see the feature working.

Co-authored-by: ivo.anjo <ivo.anjo@datadoghq.com>

Author: ivoanjo

dd-java-agent/agent-profiling/src/test/java/com/datadog/profiling/agent/ProcessContextTest.java

@@ -1,5 +1,6 @@
 package com.datadog.profiling.agent;
 
+import static org.junit.jupiter.api.Assertions.assertTrue;
 import static org.mockito.ArgumentMatchers.eq;
 import static org.mockito.Mockito.mock;
 import static org.mockito.Mockito.mockStatic;
@@ -79,24 +80,8 @@ void testRegisterSkipsWhenDisabled() {
   }
 
   @Test
-  void testRegisterSkipsByDefault() {
-    ConfigProvider configProvider = mock(ConfigProvider.class);
-    when(configProvider.getBoolean(
-            eq(ProfilingConfig.PROFILING_PROCESS_CONTEXT_ENABLED),
-            eq(ProfilingConfig.PROFILING_PROCESS_CONTEXT_ENABLED_DEFAULT)))
-        .thenReturn(ProfilingConfig.PROFILING_PROCESS_CONTEXT_ENABLED_DEFAULT);
-
-    DdprofLibraryLoader.OTelContextHolder holder =
-        mock(DdprofLibraryLoader.OTelContextHolder.class);
-
-    try (MockedStatic<DdprofLibraryLoader> ddprofMock = mockStatic(DdprofLibraryLoader.class)) {
-      ddprofMock.when(DdprofLibraryLoader::otelContext).thenReturn(holder);
-
-      ProcessContext.register(configProvider);
-
-      verify(holder, org.mockito.Mockito.never()).getReasonNotLoaded();
-      verify(holder, org.mockito.Mockito.never()).getComponent();
-    }
+  void testEnabledByDefault() {
+    assertTrue(ProfilingConfig.PROFILING_PROCESS_CONTEXT_ENABLED_DEFAULT);
   }
 
   @Test

dd-trace-api/src/main/java/datadog/trace/api/config/ProfilingConfig.java

@@ -127,7 +127,7 @@ public final class ProfilingConfig {
 
   public static final String PROFILING_PROCESS_CONTEXT_ENABLED =
       "profiling.experimental.process_context.enabled";
-  public static final boolean PROFILING_PROCESS_CONTEXT_ENABLED_DEFAULT = false;
+  public static final boolean PROFILING_PROCESS_CONTEXT_ENABLED_DEFAULT = true;
 
   public static final String PROFILING_DATADOG_PROFILER_LOG_LEVEL = "profiling.ddprof.loglevel";