Refine AntPathMatcher.combine when p1 contains '.'

Refine AntPathMatcher.combine rules to allow direct concatenation of
patterns when pattern1 does not contain '*.'. Prior to this commit
direct concatenation was allowed when pattern1 did not contain '.',
this prevented calls of the form:

	pathMatcher.combine("/1.0", "/foo/test")

from working as expected.

This commit also applies some general cleanup to the `combine` method.

Issue: SPR-10554

spring-core/src/test/java/org/springframework/util/AntPathMatcherTests.java

@@ -399,6 +399,7 @@ public class AntPathMatcherTests {
 		assertEquals("/hotels/**/booking", pathMatcher.combine("/hotels/**", "/booking"));
 		assertEquals("/hotels/booking", pathMatcher.combine("/hotels", "/booking"));
 		assertEquals("/hotels/booking", pathMatcher.combine("/hotels", "booking"));
+		assertEquals("/hotels/booking", pathMatcher.combine("/hotels/", "booking"));
 		assertEquals("/hotels/{hotel}", pathMatcher.combine("/hotels/*", "{hotel}"));
 		assertEquals("/hotels/**/{hotel}", pathMatcher.combine("/hotels/**", "{hotel}"));
 		assertEquals("/hotels/{hotel}", pathMatcher.combine("/hotels", "{hotel}"));
@@ -413,6 +414,7 @@ public class AntPathMatcherTests {
 		assertEquals("/{foo}/bar", pathMatcher.combine("/{foo}", "/bar"));	// SPR-8858
 		assertEquals("/user/user", pathMatcher.combine("/user", "/user"));	// SPR-7970
 		assertEquals("/{foo:.*[^0-9].*}/edit/", pathMatcher.combine("/{foo:.*[^0-9].*}", "/edit/")); // SPR-10062
+		assertEquals("/1.0/foo/test", pathMatcher.combine("/1.0", "/foo/test")); // SPR-10554
 	}
 
 	@Test