checkNotModified leniently handles IE-10-style If-Modified-Since values and silently proceeds if header value cannot be parsed at all

Issue: SPR-11727
(cherry picked from commit 794e859)
@Bean processing explicitly ignores bridge methods (for method overrides with return type narrowing on JDK 8)

Issue: SPR-11718
Configuration class processing explicitly skips java.* classes since we'll never find @Bean annotations there anyway

Issue: SPR-11718
ASM 5.0.2 for correct Java 7 stack map frame computations

Issue: SPR-11656