Regressions on master at commit r17-1816 vs commit r17-1806 on Linux/x86_64

[Haochen Jiang]

Regressions on master at commit r17-1816 vs commit r17-1806 on Linux/x86_64
New failures:
FAIL: g++.dg/modules/compile-std1.C -std=c++29 module-cmi std.compat (gcm.cache/std.compat.gcm)
FAIL: g++.dg/modules/compile-std1.C -std=c++29 module-cmi std.compat (gcm.cache/std.compat.gcm)
FAIL: g++.dg/modules/compile-std1.C -std=c++29 module-cmi std (gcm.cache/std.gcm)
FAIL: g++.dg/modules/compile-std1.C -std=c++29 module-cmi std (gcm.cache/std.gcm)
FAIL: g++.dg/modules/compile-std1.C -std=c++29 (test for excess errors)
FAIL: g++.dg/modules/compile-std1.C -std=c++29 (test for excess errors)
FAIL: g++.dg/plugin/std-module-exports-c++20.C -fplugin=./std_module_exports_plugin.so (test for excess errors)
FAIL: g++.dg/plugin/std-module-exports-c++20.C -fplugin=./std_module_exports_plugin.so (test for excess errors)
FAIL: g++.dg/plugin/std-module-exports-c++23.C -fplugin=./std_module_exports_plugin.so (test for excess errors)
FAIL: g++.dg/plugin/std-module-exports-c++23.C -fplugin=./std_module_exports_plugin.so (test for excess errors)
FAIL: g++.dg/plugin/std-module-exports-c++26.C -fplugin=./std_module_exports_plugin.so (test for excess errors)
FAIL: g++.dg/plugin/std-module-exports-c++26.C -fplugin=./std_module_exports_plugin.so (test for excess errors)

New passes: