roll deps (KhronosGroup#6658)

- **Roll external/abseil_cpp/ 351086314..892f51328 (2 commits)**
- **Roll external/mimalloc/ b1963961a..fef6b0dd7 (38 commits)**
- **Roll external/spirv-headers/ 1a22b1670..58006c901 (4 commits)**


---------

Co-authored-by: GitHub Actions[bot] <>
Co-authored-by: Steven Perron <stevenperron@google.com>

Author: github-actions[bot]

DEPS

@@ -3,7 +3,7 @@ use_relative_paths = True
 vars = {
   'github': 'https://github.com',
 
-  'abseil_revision': '7dcc24cf19674efc75b8e8de06b9617838b8e0e9',
+  'abseil_revision': '30bba84041ba0aadd2c31b52742b8157db047a2f',
 
   'effcee_revision': 'ae38e040cbb7e83efa8bfbb4967e5b8c8c89b55a',
 
@@ -14,9 +14,9 @@ vars = {
 
   're2_revision': '972a15cedd008d846f1a39b2e88ce48d7f166cbd',
 
-  'spirv_headers_revision': '1a22b167081842915a1c78a0b5b5a353a23284aa',
+  'spirv_headers_revision': '58006c901d1d5c37dece6b6610e9af87fa951375',
 
-  'mimalloc_revision': 'b1963961a5cdb1996c9ad2e356014089b7a94ea3',
+  'mimalloc_revision': 'fef6b0dd70f9d7fa0750b0d0b9fbb471203b94cd',
 }
 
 deps = {