CI: use -O1 optimized builds for sanitizer and valgrind runs.

ChatGPT suggested this for sanitizer runs, but valgrind gains a little
too.

Sanitizer before:	74.1-98.9(84.5+/-7.3) minutes
Sanitizer after:	11.6-15.2(13.3+/-1.2) minutes

Valgrind before:	43.3-54.1(46.8+/-3.8) minutes
Valgrind after:		40.9-49.4(43.4+/-2.5) minutes

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

Author: rustyrussell

.github/workflows/ci.yaml

@@ -118,6 +118,11 @@ jobs:
             VALGRIND: 1
             COMPILER: gcc
             DEBUG_BUILD: --enable-debugbuild
+          - CFG: compile-gcc-O1
+            VALGRIND: 1
+            COMPILER: gcc
+            COPTFLAGS_VAR: COPTFLAGS="-O1"
+            DEBUG_BUILD: --enable-debugbuild
           - CFG: compile-gcc-O3
             VALGRIND: 1
             COMPILER: gcc
@@ -133,6 +138,7 @@ jobs:
             ASAN: 1
             UBSAN: 1
             VALGRIND: 0
+            COPTFLAGS_VAR: COPTFLAGS="-O1"
             DEBUG_BUILD:
     steps:
       - name: Checkout
@@ -240,7 +246,7 @@ jobs:
       fail-fast: true
       matrix:
         include:
-          - CFG: compile-gcc
+          - CFG: compile-gcc-O1
             VALGRIND: 1
           - CFG: compile-clang-sanitizers
             VALGRIND: 0
@@ -521,7 +527,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        CFG: [compile-gcc]
+        CFG: [compile-gcc-O1]
         GROUP: [1,2,3,4,5,6,7,8,9,10]
     steps:
       - name: Checkout