Refactoring: Move MimeMap to libcore.content.type.

MimeMap is not specific to Networking (URLConnection.getFileNameMap()
is not the only client) so it didn't make sense for the class to live
in the old packet. The new packet mirrors frameworks' android.content.type
which holds the logic constructing the default instance.

The new packet is specific to this purpose (libcore.content did not
previously exist) and makes for a more sensible CorePlatformApi that
we are more likely to be able to support long term.

Bug: 124232146
Bug: 136256059
Test: atest CtsMimeMapTestCases CtsLibcoreTestCases
Change-Id: I2a6576cf6f5f06bf159a975ad40a1c09a615e9b5
diff --git a/non_openjdk_java_files.bp b/non_openjdk_java_files.bp
index 28fa59e..c080fcf 100644
--- a/non_openjdk_java_files.bp
+++ b/non_openjdk_java_files.bp
@@ -212,6 +212,7 @@
         "luni/src/main/java/libcore/api/CorePlatformApi.java",
         "luni/src/main/java/libcore/api/Hide.java",
         "luni/src/main/java/libcore/api/IntraCoreApi.java",
+        "luni/src/main/java/libcore/content/type/MimeMap.java",
         "luni/src/main/java/libcore/icu/DateIntervalFormat.java",
         "luni/src/main/java/libcore/icu/ICU.java",
         "luni/src/main/java/libcore/icu/LocaleData.java",
@@ -226,7 +227,6 @@
         "luni/src/main/java/libcore/io/Os.java",
         "luni/src/main/java/libcore/io/Streams.java",
         "luni/src/main/java/libcore/net/InetAddressUtils.java",
-        "luni/src/main/java/libcore/net/MimeMap.java",
         "luni/src/main/java/libcore/net/NetworkSecurityPolicy.java",
         "luni/src/main/java/libcore/net/event/NetworkEventDispatcher.java",
         "luni/src/main/java/libcore/timezone/CountryTimeZones.java",