Add libprofile-clang-extras when coverage is enabled.

Bug: 233660582
Test: Manually verified the lib and related flags are present when
coverage is enabled.

Change-Id: I7f03fbe56acd31016687751d10c73f2e92b2fa8c
diff --git a/android/allowlists/allowlists.go b/android/allowlists/allowlists.go
index 4ab94c3..b09b923 100644
--- a/android/allowlists/allowlists.go
+++ b/android/allowlists/allowlists.go
@@ -284,6 +284,7 @@
 		"system/core/libvndksupport":                             Bp2BuildDefaultTrueRecursively,
 		"system/core/property_service/libpropertyinfoparser":     Bp2BuildDefaultTrueRecursively,
 		"system/core/property_service/libpropertyinfoserializer": Bp2BuildDefaultTrueRecursively,
+		"system/extras/toolchain-extras":                         Bp2BuildDefaultTrue,
 		"system/incremental_delivery/incfs":                      Bp2BuildDefaultTrue,
 		"system/libartpalette":                                   Bp2BuildDefaultTrueRecursively,
 		"system/libbase":                                         Bp2BuildDefaultTrueRecursively,