AK+LibTest: Relax read size requirement for AsyncInputStream

This turned out to be a bit too strict. Streams might have sub-byte
structure which will be difficult to lex while satisfying the old size
condition. Since replacing the strict comparison with a non-strict one
doesn't break anything (including time complexity), just do this.

AK/AsyncStream.h

@@ -87,11 +87,11 @@ class AsyncResource {
 // should ensure the following: at the time of `read`, let (s_1, s_2, ..., s_n) be a sequence of
 // lengths of ReadonlyBytes returned from `peek` or `peek_or_eof` since the last read (or since the
 // creation of the stream, if there were no previous reads). If n > 1 and s_n != s_{n - 1},
-// s_{n - 1} must be strictly less than `bytes` parameter. If n == 1 and s_n == s_{n - 1} (EOF
-// has been reached), `bytes` must equal to s_n. While the behavior if the caller fails to satisfy
-// the requirement is well-defined, violation of it almost always indicates a bug in the caller's
-// code. Additionally, the asynchronous streams framework doesn't guarantee linear asymptotic
-// runtime complexity in the case of violation.
+// s_{n - 1} must be not greater than `bytes` parameter. If n == 1 and s_n == s_{n - 1} (EOF has
+// been reached), `bytes` must equal to s_n. While the behavior if the caller fails to satisfy the
+// requirement is well-defined, violation of it almost always indicates a bug in the caller's code.
+// Additionally, the asynchronous streams framework doesn't guarantee linear asymptotic runtime
+// complexity in the case of violation.
 //
 // Note that `read` always returns exactly `bytes` bytes. If `bytes` is larger than s_n or n is 0,
 // `read` will return more data than previously peeked (by reading the stream, obviously).

Userland/Libraries/LibTest/AsyncTestStreams.cpp

@@ -140,7 +140,7 @@ ReadonlyBytes AsyncMemoryInputStream::buffered_data_unchecked(Badge<AsyncInputSt
 void AsyncMemoryInputStream::dequeue(Badge<AsyncInputStream>, size_t bytes)
 {
     m_read_head += bytes;
-    VERIFY(m_last_enqueue < m_read_head && m_read_head <= m_peek_head);
+    VERIFY(m_last_enqueue <= m_read_head && m_read_head <= m_peek_head);
 }
 
 AsyncMemoryOutputStream::AsyncMemoryOutputStream(StreamCloseExpectation expectation)