Change QUIC uses of gmock regex to simpler syntax

This fixes Chromium test failures because on some platforms gmock does not support bracket syntax like [0-9]

gfe-relnote: n/a, test-only
PiperOrigin-RevId: 254031357
Change-Id: Icc25b58afaaf0970fc0a78de936d52db3f433a05
diff --git a/quic/core/http/quic_spdy_stream_test.cc b/quic/core/http/quic_spdy_stream_test.cc
index 63d5ba3..a1e4fab 100644
--- a/quic/core/http/quic_spdy_stream_test.cc
+++ b/quic/core/http/quic_spdy_stream_test.cc
@@ -262,10 +262,10 @@
   if (version_uses_qpack) {
     EXPECT_CALL(
         *connection_,
-        CloseConnection(QUIC_HEADERS_STREAM_DATA_DECOMPRESS_FAILURE,
-                        testing::MatchesRegex(
-                            "Too large headers received on stream [0-9]+"),
-                        _));
+        CloseConnection(
+            QUIC_HEADERS_STREAM_DATA_DECOMPRESS_FAILURE,
+            testing::MatchesRegex("Too large headers received on stream \\d+"),
+            _));
   } else {
     EXPECT_CALL(*session_,
                 SendRstStream(stream_->id(), QUIC_HEADERS_TOO_LARGE, 0));
@@ -1796,7 +1796,7 @@
       *connection_,
       CloseConnection(QUIC_DECOMPRESSION_FAILURE,
                       testing::MatchesRegex(
-                          "Error decompressing header block on stream [0-9]+: "
+                          "Error decompressing header block on stream \\d+: "
                           "Incomplete header block."),
                       _))
       .WillOnce(