Simplify and consolidate type printing (#5816)

When printing Binaryen IR, we previously generated names for unnamed heap types
based on their structure. This was useful for seeing the structure of simple
types at a glance without having to separately go look up their definitions, but
it also had two problems:

1. The same name could be generated for multiple types. The generated names did
not take into account rec group structure or finality, so types that differed
only in these properties would have the same name. Also, generated type names
were limited in length, so very large types that shared only some structure
could also end up with the same names. Using the same name for multiple types
produces incorrect and unparsable output.

2. The generated names were not useful beyond the most trivial examples. Even
with length limits, names for nontrivial types were extremely long and visually
noisy, which made reading disassembled real-world code more challenging.

Fix these problems by emitting simple indexed names for unnamed heap types
instead. This regresses readability for very simple examples, but the trade off
is worth it.

This change also reduces the number of type printing systems we have by one.
Previously we had the system in Print.cpp, but we had another, more general and
extensible system in wasm-type-printing.h and wasm-type.cpp as well. Remove the
old type printing system from Print.cpp and replace it with a much smaller use
of the new system. This requires significant refactoring of Print.cpp so that
PrintExpressionContents object now holds a reference to a parent
PrintSExpression object that holds the type name state.

This diff is very large because almost every test output changed slightly. To
minimize the diff and ease review, change the type printer in wasm-type.cpp to
behave the same as the old type printer in Print.cpp except for the differences
in name generation. These changes will be reverted in much smaller PRs in the
future to generally improve how types are printed.

1 files changed, 1 insertions, 1 deletions

diff --git a/test/br_to_exit.wasm.fromBinary b/test/br_to_exit.wasm.fromBinary
index e81b1db2a..faee4e21b 100644
--- a/test/br_to_exit.wasm.fromBinary
+++ b/test/br_to_exit.wasm.fromBinary
@@ -1,5 +1,5 @@
 (module
- (type $none_=>_none (func))
+ (type $0 (func))
  (func $0
   (block $label$0
    (br $label$0)