[SkQP/Android] Replace -Weverything with -Wextra

-Weverything is not recommended, use -Wextra.

CQ_INCLUDE_TRYBOTS=skia.primary:Build-Debian9-Clang-x86-devrel-Android_SKQP,Test-Debian9-Clang-NUC7i5BNK-CPU-Emulator-x86-devrel-All-Android_SKQP

Bug: b/143713277
Test: mma
Change-Id: Ibaca86bd52348d544a8109b25ae013001444935d
Reviewd-on: https://android-review.googlesource.com/1163299
Cherry-pick: 29cd4eca88df5fafde51ee9a50e3deb96263fc64
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/253956
Reviewed-by: Derek Sollenberger <djsollen@google.com>
Commit-Queue: Hal Canary <halcanary@google.com>
diff --git a/BUILD.gn b/BUILD.gn
index 843f9b9..349ac1f 100644
--- a/BUILD.gn
+++ b/BUILD.gn
@@ -2015,7 +2015,13 @@
   }
 
   if (!is_win) {
-    test_lib("skqp_lib") {
+    source_set("skqp_lib") {
+      check_includes = false
+      testonly = true
+      if (!is_official_build) {
+        configs -= [ "//gn:warnings" ]
+      }
+      public_configs = [ ":skia_private" ]
       defines =
           [ "SK_SKQP_GLOBAL_ERROR_TOLERANCE=$skia_skqp_global_error_tolerance" ]
       sources = [
@@ -2053,8 +2059,12 @@
     }
   }
   if (is_android) {
-    test_app("skqp_app") {
-      is_shared_library = true
+    shared_library("libskqp_app") {
+      configs += [ ":skia_private" ]
+      if (!is_official_build) {
+        configs -= [ "//gn:warnings" ]
+      }
+      testonly = true
       sources = [
         "tools/skqp/src/jni_skqp.cpp",
       ]