More Valgrind suppressions:

 - suppress leaks from extensions::ApiTestBase::SetUp() and extensions::MojoPrivateApiTest_Define_Test::TestBody() (issue 448700)

BUG=448700
TBR=timurrrr@chromium.org
NOTRY=true

Review URL: https://codereview.chromium.org/850893002

Cr-Commit-Position: refs/heads/master@{#311459}

tools/valgrind/memcheck/suppressions.txt

@@ -3530,3 +3530,24 @@
    ...
    fun:_ZN3gpu5gles252GLES2ImplementationTest_TexImage3DSingleCommand_Test8TestBodyEv
 }
+{
+   bug_448700_a
+   Memcheck:Leak
+   fun:_Znw*
+   ...
+   fun:_ZN10extensions11ApiTestBase15RegisterModulesEv
+   fun:_ZN10extensions11ApiTestBase5SetUpEv
+}
+{
+   bug_448700_b
+   Memcheck:Leak
+   fun:_Znw*
+   ...
+   fun:_ZN10extensions12_GLOBAL__N_111TestNatives24GetObjectTemplateBuilderEPN2v87IsolateE
+   fun:_ZN3gin13WrappableBase14GetWrapperImplEPN2v87IsolateEPNS_11WrapperInfoE
+   fun:_ZN3gin9WrappableIN10extensions12_GLOBAL__N_111TestNativesEE10GetWrapperEPN2v87IsolateE
+   fun:_ZN3gin12CreateHandleIN10extensions12_GLOBAL__N_111TestNativesEEENS_6HandleIT_EEPN2v87IsolateEPS5_
+   fun:_ZN10extensions12_GLOBAL__N_111TestNatives6CreateEPN2v87IsolateERKN4base8CallbackIFvvEEE
+   fun:_ZN10extensions11ApiTestBase7RunTestERKSsS2_
+   fun:_ZN10extensions30MojoPrivateApiTest_Define_Test8TestBodyEv
+}